The numbers are what you need to use in your .tim file. For characters and named objects you should be able to find the right codes fairly easily. Unfortunately, generic obstacles like rocks aren't as easy to figure out exactly which is which, and will require some trial and error.

Those variable, like SNK, SNKT, WALL_REF, TAR_SEI, are hard to understand what is mean behind it's naming. Other hand, there has some variable name that easy to understand, like TI_MIMIC_... . There also has some variable that has 'A' on it, seems used for frame 2 of an animated monster.